WEB-INF/flex/services-config.xml
in the channels definition at the top:

<channels>
    <!--USED IN THE LIVE ENVIRONMENT-->
          <!--channel ref="my-graniteamf-secure"/-->
    <!--USED IN THE LOCAL/DEV ENVIRONMENT-->
          <channel ref="my-graniteamf"/>
</channels>

Then in the channel definition below we have both definitions:

<channel-definition id="my-graniteamf"
	class="mx.messaging.channels.AMFChannel">
	<endpoint
		uri="http://{server.name}:{server.port}/{context.root}/graniteamf/amf"
		class="flex.messaging.endpoints.AMFEndpoint" />
</channel-definition>
<channel-definition id="my-graniteamf-secure"
	class="mx.messaging.channels.SecureAMFChannel">
	<endpoint
		uri="https://{server.name}:443/{context.root}/graniteamf/amf"
		class="flex.messaging.endpoints.SecureAMFEndpoint" />
</channel-definition>

Click Here to Download: services-config.xml

We couldn’t get {server.port} to work correctly, so we’re forcing the port in the address for now.

The only problem with this is you have to remember to switch the AMF channel before deploying.  It’s on our checklist before doing the full deploy, but we’re most likely going to add it to the ant task list to deploy dev, deploy live.  Something like that.

The KEY THING TO REMEMBER is this: although this file is deployed with the war/ear, it is ALSO COMPILED INTO THE APPLICATION SWF when it is built.  Make sure to change it locally and rebuild your swf before posting, or you will see no change in your app. (found this out after a significant amount of time changing the file on the server to no avail…)

(Ref: http://www.mail-archive.com/discussion@affug.com/msg00605.html)